If you work in an office -- with other people -- you know that uninterrupted chunks of time are rare. To gauge just how many times you're interrupted in, say, an afternoon, try this: Create an hour-long playlist for your iPhone or iPod. See if you can consistently get all the way through it in an afternoon. The idea here is that you'll be hitting pause and removing your earbuds every time the phone rings or when someone walks in.
If you struggle to get through a full hour of music in a typical four-hour afternoon, point it out to your boss. Use it to make a case to work remotely more often.